Did you notice that President Obama didn’t say the words “climate change” or global warming” in his 7,000-word State of the Union speech? He described government support for clean energy as

an investment that will strengthen our security, protect our planet, and create countless new jobs for our people

Partly this is repackaging, and not in a good way. Partly it’s a recognition that we’re utterly failing, here in the U.S. and globally, to curb the greenhouse gas emissions that cause global warming. (See the chart at the end of this blogpost.) That’s not something the president wants people to think about. It’s actually not something that anyone wants to think about–not environmentalists, because it leads to a sense of hopelessness, not free-market ideologues, because it’s a glaring example of market failure, not the press because, well, climate change has become an old and depressing story,.

But ignoring the threat of climate catastrophe won’t make it disappear.

So, sooner or later, as people come to see the threat, scientific and political attention will turn to geoengineering—deliberate intervention in the climate system to moderate global warming. By coincidence, on the day after the president spoke, scientists at UNESCO published a guide to one of the early approaches to geoengineering, a technique known as ocean fertilization or iron fertilization. The idea here is that sprinkling iron dust atop the oceans will stimulate plant growth and suck large quantities of carbon dioxide out of the air.

Ocean fertilization has been bruited about for decades. “Give me a half tanker of iron, and I will give you an ice age,” a scientist named John Martin said back in the 1980s. The technique attracted some notoriety more recently when a couple of U.S-based startup companies, Climos and Planktos, were created to explore the idea. (I wrote about Climos for Fortune.com in 2008.)

Imagine a fleet of 1,500 remote-controlled, wind-powered ships, sailing the world’s oceans, spewing salt water into the air to whiten clouds, so they block more of the sun and cool an overheating planet.

Or think of trillions of tiny mirrors, sent into orbit, to reflect the sun’s rays. Or artificial trees that suck a ton of carbon a day out of the atmosphere. Or iron filings, sprinkled on seas, to rapidly grow phytoplankton, which absorb CO2.

These emergency strategies for curbing global warming aren’t crazy schemes. Well, maybe they are crazy schemes. But serious people say we should start taking them seriously, as a last-ditch option to deal with the threat of catastrophic climate disruptions.

The latest to do so is David G. Victor, a professor of law at Stanford who directs a program on energy and sustainable development at the university. With four academic colleagues–Victor M. Granger, Jay Apt, John Steinbruner and Katherine Ricke–Victor has written an essay in Foreign Affairs called “The Geoengineering Option” that calls for more scientific research and policy debate about geoengineering.

I ask him by phone why he became interested in geoengineering which, by his own account, is on fringe of climate science and politics.

“You can’t help but look at the politics and the science of global warming today without becoming extremely pessimistic,” Victor says.

“Barely a month goes by without a new report saying that warming is happening faster,” he goes on. “It’s a really worrisome picture.”

But doesn’t the debate that’s beginning in Washington over climate-change regulation give him reason for hope?

“The Obama proposals are step in the right direction and they’re better than what we were doing before which was, roughly, nothing,” he replies. But as currently proposed, the cap-and-trade system to regulate greenhouse gases doesn’t go far enough to reduce the use of fossil fuels and promote renewable energy. Gasoline prices, for example, would rise an estimated 15 cents a gallon under the plan, not enough to matter.

And so, the argument goes, when measured against current efforts to mitigate climate change—which, in truth, require the top-to-bottom transformation of the global energy economy, despite a mostly-apathetic populace and over the objections of deeply entrenched industries—geoengineering doesn’t look so crazy.

It’s not just Victor and his colleagues who say we should reconsider geoengineering.. Last fall, Scientific American published a long analysis of the science and politics of geoengineering, with a focus on pumping sulfur dioxide into the stratosphere, as volcanoes do. Popular Mechanics described “Five Big Plans to Stop Global Warming,” which generated a lot of buzz on the web. Treehugger used the illustration below to consider the topic back in 2007.

Yet, as Victor and his colleagues point out in Foreign Affairs, there’s a scarcity of scientific research into the topic:

Despite years of speculation and vague talk, peer-reviewed research on geoengineering is remarkably scarce. Nearly the entire community of geoengineering scientists could fit comfortably in a single university seminar room, and the entire scientific literature on the subject could be read during the course of a transatlantic flight. Geoengineering continues to be considered a fringe topic.

Partly that’s because environmentalists have been loathe to talk about geoengineering, for fear that people will think there’s a magic bullet out there that will enable them to avoid hard choices about the costs of moving away from fossil fuels and towards for renewable power.

It’s also because we have come to understand the limits of science and engineering, thanks to such events as Chernobyl, the Exxon Valdez oil spill, the space shuttle Challenger disaster. Tinkering with the earth’s climate is no trivial matter. According to Victor and his co-authors, altering the earth’s albedo—that’s a term to describe the extent to which an object reflects light from the sun—would also affect

atmospheric circulation, rainfall and other aspects of the hydrologic cycle…Such changes could increase the risk of major droughts in some regions and have a major impact on agriculture and the supply of fresh water.

“This scares the hell out of people, and for good reason,” Victor says.

The thing is, any nation fearing the impact of climate change could, in theory, begin engineering the planet without consulting the rest of us. Who’s going to stop it? The UN? Even in the U.S., it’s not clear who’s responsible for geoengineering. NASA? The Pentagon? The National Science Foundation? Ira Flatow?

“It doesn’t logically fit in any one place in government,” Victor says.

Some companies think there are profits to be made from geoengineering. Last year, I wrote a column (“Dumping Iron”) about Climos, a company that hopes to deploy ocean iron fertilization to generate revenues from carbon offsets.

What’s needed, Victor tells me, is government-backed research carried out by academic scientists. “The science needs to be done in a way that is open and transparent and involves serious review and scrutiny,” he says. At the same time, governments need to begin talking about how to manage and regulate geoengineering. As Victor and his co-authors put it:

“Politicians must take geoengineering seriously because it is cheap, easy and takes only one government with sufficient hubris or desperation to set it into motion.”